1. Field of the Invention
The present invention relates to a lighting apparatus for vehicles such as motor vehicles, and more specifically, to a vehicle lighting apparatus comprising lamp deflection angle controlling means for controlling the changes in direction of beam of the lamp corresponding to the traveling conditions, for example, an adaptive front-lighting system (hereinafter referred to as AFS) for ensuring driving safety against a disorder occurred in the AFS.
2. Description of the Related Art
The AFS proposed for enhancing driving safety of motor vehicles detects information on the steering angle of the steering wheel SW of the motor vehicles, the vehicle speed, and other traveling conditions of the motor vehicles by the sensor 1, and outputs the detected output to the electronic control unit 2 (hereinafter referred to as ECU) as shown in FIG. 1. The ECU 2 controls the swivel type lights 3R, 3L provided respectively on the left and right of the front portion of the motor vehicle, that is, the headlamps 3 that the direction of radiation can be deflected in the lateral direction based on the supplied sensor outputs. Such swivel type lights 3R, 3L may include, as a structure that can turn the reflector provided in the headlamp in the horizontal direction, a structure that can turn the reflector by the driving source such as a motor or the like, which is referred to as an actuator in this specification. According to the AFS in this type, when the motor vehicle travels on the curved road, the portion of the road ahead of the curve may be illuminated corresponding to the traveling speed of the motor vehicle, thereby effective in improving driving safety.
However, when a failure occurred in the AFS, especially when it became uncontrollable in a state in which the direction of radiation of the headlamp is deflected either to the left or the right with respect to the straight ahead direction of the motor vehicle, the forward of the motor vehicle cannot be illuminated when motor vehicle is driving straight ahead or turning along the curve in the opposite direction and thus deteriorate driving safety. Failures in the AFS includes, in the AFS shown in FIG. 1 for example, a case where the sensor 1 is broken down and thus the sensor outputs is not supplied from the sensor 1 to the ECU2, a case where the ECU 2 is broken down, and a case where the actuator in the headlamp 3 is broken down, and in any cases, the AFS cannot function normally. Therefore, the AFS is required to have a capability that prevents deteriorating of safety even when a failure occurred, that is, failsafe capability.
The object of the present invention is to provide a vehicle lighting apparatus having failsafe capability ensuring driving safety even when a disorder occurred in the AFS.
The present invention is a vehicle lighting apparatus including lamp deflection angle controlling means for controlling the changes in deflection angle of the direction of radiation of the lamp corresponding to the traveling conditions of the vehicle, wherein the lamp deflection angle controlling means comprises abnormality detecting means for detecting abnormality of the deflection angle detecting means for detecting the deflection angle of the lamp, and a reference angular position setting means for setting the deflection angle of the lamp to the predetermined reference angular position when abnormality occurred in the deflection angle detecting means. The reference angular position setting means comprises a motor for changing the deflection angle of the lamp, rotational position detecting means for detecting the rotational position of the motor, and motor controlling means for driving and controlling the motor, and the motor controlling means is adapted to be capable of controlling the motor to rotate in one direction to the locked state when abnormality occurred in the lamp deflecting angle detecting means and of controlling the motor to rotate in the reverse direction by a prescribed rotational angle after the motor is brought into the locked state. The motor of the reference angular position setting means includes a hall element for supplying pulse signal in accordance with the rotational operation of the motor, and the controlling means is preferably adapted to perform control to count the number of pulses of the pulse signal supplied from the hall element as control to rotate the motor means in the reverse direction by a prescribed rotational angle. Further, the lamp deflection angle controlling means may comprise a sensor for detecting the steering direction of the vehicle, a control unit for supplying the lamp defection angle signal based on the sensor outputs, and an actuator for deflecting the lamp based on the lamp deflection angle signal, wherein the abnormality detecting means are provided in the control unit and the actuator respectively, so that the reference angular position setting means is actuated without the control unit along the path when abnormality is detected by the abnormality detecting means in the latter.
According to the present invention, when the deflection angle of the lamp in the AFS cannot be detected and thus the system lapsed into malfunction, the reference angular position setting means is actuated to fix the deflection angle of the lamp to the reference position so that the condition in which the lamp is fixed to the abnormal deflection angle with respect to the traveling direction of the vehicle can be prevented before happens, and thus failsafe that is favorable in terms of traffic safety may be realized. As reference angular position setting means, such a construction that the motor for deflecting the lamp is rotated in one direction to the locked state, and from this locked state, the motor that is rotated by a given amount is rotated by the given amount in the reverse direction may be employed, and by utilizing pulse signal supplied from the hall element attached on the motor in this case, additional components aside from the existing motor is not necessary, thereby preventing increase in complexity of construction and in the cost.